1. Field of the Invention
This invention relates to a copper-hardened permanent-magnet alloy consisting of cobalt, copper and at least one of the rare earth metals (RE) having atomic numbers 57-71, and also to a method of producing such an alloy. This invention also relates to certain uses of this novel alloy.
2. Description of the Prior Art
In U.S. Pat. No. 3,560,200 (German Pat. No. 1,915,358) there is disclosed copper-hardened permanent-magnet alloys consisting of the components A (cobalt or iron), RE (at least one element from the group consisting of samarium, cerium, gadolinium, praseodymium, lanthanum, yttrium, neodymium and hafnium) and B (copper). In that reference, it is disclosed that hardening of the alloys with the nonmagnetic copper results in a considerable decrease in the wall movement of the magnetic domains, so that an increasing proportion of component B increases the coercive force. On the other hand, increasing the proportion of the magnetic component A (e.g., Co) improves the remanence of the alloy. However, in the above-mentioned patent the disclosed alloys, (Co, Cu).sub.x Sm or (Co,Cu).sub.x Ce, with x = 5, 5.5, 6.24, 6.75 and 8.5, exhibit high values of coercive force, H.sub.C, and remanence, B.sub.r, only for x = 5 and then only after heat treatment. For many applications it would be most desirable to have magnetic alloys from which permanent magnets could be produced having optimal magnetic properties without concomitant increase in cost.